This adds high-level descriptions of the scheduler structures, the
user and system stacks, error handling, and synchronization.

Change-Id: I1eed97c6dd4a6e3d351279e967b11c6e64898356
Reviewed-on: https://go-review.googlesource.com/34290Reviewed-by: Rick Hudson <rlh@golang.org>

The comment describing the overall GC algorithm at the top of mgc.go
has gotten woefully out-of-date (and was possibly never
correct/complete). Update it to reflect the current workings of the
GC and the set of phases that we now divide it into.

Change-Id: I02143c0ebefe9d4cd7753349dab8045f0973bf95
Reviewed-on: https://go-review.googlesource.com/34711Reviewed-by: Rick Hudson <rlh@golang.org>

If one of the c.Get(ts.URL) results in an error, the child goroutine
calls t.Errorf, but the test goroutine gets stuck waiting for <-gotReqCh,
so the test hangs and the program is eventually killed (after 10 minutes!).
Whatever might have been printed to t.Errorf is never seen.
Adjust test so that the test fails cleanly in this case.

Still trying to debug why c.Get might fail.
It seems to have something to do with occasional connection
failures on macOS Sierra.

Change-Id: Ia797787bd51ea7cd6deb1192aec89c331c4f2c48
Reviewed-on: https://go-review.googlesource.com/34836
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Currently, the check for legal pointers in stack copying uses
_PageSize (8K) as the minimum legal pointer. By default, Linux won't
let you map under 64K, but

1) it's less clear what other OSes allow or will allow in the future;

2) while mapping the first page is a terrible idea, mapping anywhere
above that is arguably more justifiable;

3) the compiler only assumes the first physical page (4K) is never
mapped.

Make the runtime consistent with the compiler and more robust by
changing the bad pointer check to use 4K as the minimum legal pointer.

This came out of discussions on CLs 34663 and 34719.

Change-Id: Idf721a788bd9699fb348f47bdd083cf8fa8bd3e5
Reviewed-on: https://go-review.googlesource.com/34890
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

Change-Id: I1c2e17b25ca91be37a18c47e70678c3753070fb8
Reviewed-on: https://go-review.googlesource.com/34827Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>

We cannot assume that the platform running documentation service is
the target platform.

Change-Id: I241ed6f8778169faac9ef49e11dcd40f7422cccc
Reviewed-on: https://go-review.googlesource.com/34750
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fixes #18392.

Avoid nil dereferencing n.Right when dealing with non-existent
self referenced interface methods e.g.
type A interface{
  Fn(A.Fn)
}

Instead, infer the symbol name from n.Sym itself.

Change-Id: I60d5f8988e7318693e5c8da031285d8d7347b771
Reviewed-on: https://go-review.googlesource.com/34817
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Change-Id: I184c86edaaaa71c26bc7360c8b995015f30fe137
Reviewed-on: https://go-review.googlesource.com/34819Reviewed-by: Russ Cox <rsc@golang.org>

Be consistent on whether the http proxy environment variables are
respected regardless of whether -insecure is used.

Updates #18519

Change-Id: Ib157eaacfd342dd3bfcd03e64da18c98c609cae3
Reviewed-on: https://go-review.googlesource.com/34818
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

This change uses runtime.support_bmi2 as an additional condition
to examine the usability of AVX2 version algorithm, fixes
the crash on the platfrom which supports AVX2 but not support BMI2.

Fixes #18512

Change-Id: I408c0844ae2eb242dacf70cb9e8cec1b8f3bd941
Reviewed-on: https://go-review.googlesource.com/34851Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

The existing implementations on AMD64 only detects AVX2 usability,
when they also contains BMI (bit-manipulation instructions).
These instructions crash the running program as 'unknown instructions'
on the architecture, e.g. i3-4000M, which supports AVX2 but not
support BMI.

This change added the detections for BMI1 and BMI2 to AMD64 runtime with
two flags as the result, `support_bmi1` and `support_bmi2`,
in runtime/runtime2.go. It also completed the condition to run AVX2 version
in packages crypto/sha1 and crypto/sha256.

Fixes #18512

Change-Id: I917bf0de365237740999de3e049d2e8f2a4385ad
Reviewed-on: https://go-review.googlesource.com/34850Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

When I wrote the lines

	bin/
	pkg/

I was trying to match just the top-level bin and pkg directories, and I put the
final slash in because 'git help gitignore' says:

       o   If the pattern does not contain a slash /, Git treats it as a shell
           glob pattern and checks for a match against the pathname relative
           to the location of the .gitignore file (relative to the toplevel of
           the work tree if not from a .gitignore file).

       o   Otherwise, Git treats the pattern as a shell glob suitable for
           consumption by fnmatch(3) with the FNM_PATHNAME flag: wildcards in
           the pattern will not match a / in the pathname. For example,
           "Documentation/*.html" matches "Documentation/git.html" but not
           "Documentation/ppc/ppc.html" or
           "tools/perf/Documentation/perf.html".

Putting a trailing slash was my way of opting in to the "rooted path" semantics
without looking different from the surrounding rooted paths like "src/go/build/zcgo.go".

But HA HA GIT FOOLED YOU! above those two bullets the docs say:

       o   If the pattern ends with a slash, it is removed for the purpose of
           the following description, ...

Change all the patterns to use a leading slash for "rooted" behavior.

This bit me earlier today because I had a perfectly reasonable source
code directory go/src/cmd/go/testdata/src/empty/pkg that was
not added by 'git add empty'.

Change-Id: I6f8685b3c5be22029c33de9ccd735487089a1c03
Reviewed-on: https://go-review.googlesource.com/34832Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fixes #18500

Change-Id: I4dddd1b99aecf86b9431b0c14f452152dff9b95a
Reviewed-on: https://go-review.googlesource.com/34816Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #18494

Change-Id: I8a190acae6d5f1d20d4e4e4547d84e10e8a7fe68
Reviewed-on: https://go-review.googlesource.com/34793Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

Fixes #18506

Change-Id: I6b0b107296311178938609e878e1ef47a30a463f
Reviewed-on: https://go-review.googlesource.com/34814Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fixes #18447

Change-Id: I5d60c3632a5ce625d3bac9d85533ce689e301707
Reviewed-on: https://go-review.googlesource.com/34813Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

No test because in practice these errors never occur.

Change-Id: I11c77893ae931fc621c98920cba656790d18ed93
Reviewed-on: https://go-review.googlesource.com/34811
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Fixes #18486.

Change-Id: I359dc4169e04b4123bd41679ea939b06fa754ac2
Reviewed-on: https://go-review.googlesource.com/34830
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

For #18496.

Change-Id: I50ced7c9f0fe5d9c627eef1f59a7f73be742e04c
Reviewed-on: https://go-review.googlesource.com/34831
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Otherwise 64k pages don't map correctly.

Fixes #18408.

Change-Id: I85f56682531566d1ff5c655640cd58509514aee8
Reviewed-on: https://go-review.googlesource.com/34629
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

Android on ChromeOS uses a restrictive seccomp filter that blocks
sched_getaffinity, leading this code to index a slice by -errno.

Change-Id: Iec09a4f79dfbc17884e24f39bcfdad305de75b37
Reviewed-on: https://go-review.googlesource.com/34794Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>

Given
	var t struct{ lock sync.Mutex }
	var fntab []func(t)
	f(a(), b(&t), c(), fntab[0](t))

Before:
	function call copies lock value: struct{lock sync.Mutex} contains sync.Mutex

After:
	call of fntab[0] copies lock value: struct{lock sync.Mutex} contains sync.Mutex

This will make diagnosis easier when there are multiple function calls per line.

Change-Id: I9881713c5671b847b84a0df0115f57e7cba17d72
Reviewed-on: https://go-review.googlesource.com/34730Reviewed-by: Ian Lance Taylor <iant@golang.org>

Change-Id: Ia97d770cd942a49a34c733643ced7490fc31c736
Reviewed-on: https://go-review.googlesource.com/34795
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Change-Id: I9e37aece5ace374e89bee70962a19f76ae3266bc
Reviewed-on: https://go-review.googlesource.com/34646
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Fixes misc/cgo/testsigfwd, enabled for mips{,le} with the next commit
(https://golang.org/cl/34646).

Change-Id: I2bec894b0492fd4d84dd73a4faa19eafca760107
Reviewed-on: https://go-review.googlesource.com/34645Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Clean up the phrasing a little bit, make the comment fit in 80
characters, and fix the spelling of "guard."

Change-Id: I688a3e760b8d67ea83830635f64dff04dd9a5911
Reviewed-on: https://go-review.googlesource.com/34792Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Previously Tx.done was being set in close, but in a Tx
rollback and Commit are the real closing methods,
and Tx.close is just a helper common to both. Prior to this
change a multiple rollback statements could be called, one
would enter close and begin closing it while the other was
still in rollback breaking it. Fix that by setting done
in rollback and Commit, not in Tx.close.

Fixes #18429

Change-Id: Ie274f60c2aa6a4a5aa38e55109c05ea9d4fe0223
Reviewed-on: https://go-review.googlesource.com/34716Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

It doesn't work if the package name includes a '.' or a non-ASCII
character (or '%', '"', or a control character).  See #16710 and CL 31970.

Update #18246.

Change-Id: I1487f462a3dc7b0016fce3aa1ea6239b226e6e39
Reviewed-on: https://go-review.googlesource.com/34791Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Updates http2 to x/net/http2 git rev 8fd7f25 for:

    http2: clear WriteTimeout in Server
    https://golang.org/cl/34724

And un-skip the new test. (The new test is a slow test, anyway, so
won't affect builders or all.bash, but I verified it now passes.)

Updates #18437

Change-Id: Ia91ae702edfd23747a9d6b61da284a5a957bfed3
Reviewed-on: https://go-review.googlesource.com/34729
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
Reviewed-by: Kale B <kale@lemnisys.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Current handling of WriteTimeout for http2 does not
extend the timeout on new streams. Disable the WriteTimeout
in http2 for 1.8 release.

Updates #18437

Change-Id: I20480432ab176f115464434645defb56ebeb6ece
Reviewed-on: https://go-review.googlesource.com/34723Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Avoid potential race conditions by clarifying to implemntors of the
ReverseProxy interface, the lifetime of provided http.Request structs.

Fixes #18456
Change-Id: I46aa60322226ecc3a0d30fa1ef108e504171957a
Reviewed-on: https://go-review.googlesource.com/34720Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Remove unneeded second colon.

Remove unneeded space at the beginning of a line (before a tab).

Regenerate alldocs.go with mkalldocs.sh.

Updates https://golang.org/cl/28783.
Updates https://golang.org/cl/29650.
Fixes #18448.

Change-Id: I1830136a2b760827d4cec565744807a0fd147584
Reviewed-on: https://go-review.googlesource.com/34718Reviewed-by: Rob Pike <r@golang.org>

Fixes #6772.

Lock-in test for invalid range loop: repeated variables in range declaration.

Change-Id: I37dd8b1cd7279abe7810deaf8a5d485c5c3b73ca
Reviewed-on: https://go-review.googlesource.com/34714Reviewed-by: Keith Randall <khr@golang.org>

This is a follow-up for https://golang.org/cl/24340.

Updates #14664.
Fixes #18374.

Change-Id: I2831556a9014d30ec70d5f91943d18c33db5b390
Reviewed-on: https://go-review.googlesource.com/34630Reviewed-by: Rob Pike <r@golang.org>
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: Iae8cdcd84e9b5f5d7c698abc6da3fc2af0ef839a
Reviewed-on: https://go-review.googlesource.com/34710Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

Fixes #5790.
Fixes #18421.

* Lock in _ = x1/x2 divide by zero runtime panics since
it is actually evaluated and not discarded as in previous
versions before Go1.8.
* Update a test that was skipping over zerodivide tests
that expected runtime panics, enabling us to check for
the expected panics.

Change-Id: I0af0a6ecc19345fa9763ab2e35b275fb2d9d0194
Reviewed-on: https://go-review.googlesource.com/34712Reviewed-by: Keith Randall <khr@golang.org>

Change-Id: I24c6d312f7d0ce52e1958e8031fc8249af0dfca9
Reviewed-on: https://go-review.googlesource.com/34669Reviewed-by: Minux Ma <minux@golang.org>

Previous changes started using the full filename for object files
on graph nodes, instead of just the file basename. The basename
was still being used when selecting mappings to disassemble for
weblist and disasm commands, causing a mismatch.

This fixes #18385. It was already fixed on the upstream pprof.

Change-Id: I1664503634f2c8cd31743561301631f12c4949c9
Reviewed-on: https://go-review.googlesource.com/34665Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

In Go 1.8, we'd removed the Transport's Request.Body
one-byte-Read-sniffing to disambiguate between non-nil Request.Body
with a ContentLength of 0 or -1. Previously, we tried to see whether a
ContentLength of 0 meant actually zero, or just an unset by reading a
single byte of the Request.Body and then stitching any read byte back
together with the original Request.Body.

That historically has caused many problems due to either data races,
blocking forever (#17480), or losing bytes (#17071). Thus, we removed
it in both HTTP/1 and HTTP/2 in Go 1.8. Unfortunately, during the Go
1.8 beta, we've found that a few people have gotten bitten by the
behavior change on requests with methods typically not containing
request bodies (e.g. GET, HEAD, DELETE). The most popular example is
the aws-go SDK, which always set http.Request.Body to a non-nil value,
even on such request methods. That was causing Go 1.8 to send such
requests with Transfer-Encoding chunked bodies, with zero bytes,
confusing popular servers (including but limited to AWS).

This CL partially reverts the no-byte-sniffing behavior and restores
it only for GET/HEAD/DELETE/etc requests, and only when there's no
Transfer-Encoding set, and the Content-Length is 0 or -1.

Updates #18257 (aws-go) bug
And also private bug reports about non-AWS issues.

Updates #18407 also, but haven't yet audited things enough to declare
it fixed.

Change-Id: Ie5284d3e067c181839b31faf637eee56e5738a6a
Reviewed-on: https://go-review.googlesource.com/34668
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

CL 33652 removed the fake auxv for Android, and replaced it with
a /proc/self/auxv fallback. When /proc/self/auxv is unreadable,
however, hardware capabilities detection won't work and the runtime
will mistakenly think that floating point hardware is unavailable.

Fix this by always assuming floating point hardware on Android.

Manually tested on a Nexus 5 running Android 6.0.1. I suspect the
android/arm builder has a readable /proc/self/auxv and therefore
does not trigger the failure mode.

Change-Id: I95c3873803f9e17333c6cb8b9ff2016723104085
Reviewed-on: https://go-review.googlesource.com/34641Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>
Run-TryBot: Elias Naur <elias.naur@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>